The present invention relates to a memory module, and more particularly to a memory module, which is configured to increase capacity and improve the mounting reliability of a semiconductor package.
The packaging technologies for semiconductor integrated circuits have been continuously developed to meet the demands for miniaturization and mounting reliability. For example, the demand for miniaturization has advanced the technology development of packages to reduce the package size to approach the size of a chip, and the demand for mounting reliability has highlighted the importance of the technology related to improving efficiency of the mounting tasks and improving mechanical and electrical reliability after the mounting.
As miniaturization and high functionality are required for electronic devices, development of high capacity memory modules has been the focus of various technology development efforts.
High integration of memory cells is one method available to realize a high capacity memory module; however, high integration of as much as possible in number of memory cells on a limited size available in a semiconductor chip is not easy to accomplish, as it not only requires the high precision technology such as that for attaining the precise and fine line widths is required for high integration of memory cells but also requires a rather lengthy development period.
Therefore, as a different approach to realize high capacity memory modules, the technology trend is directed to developing new ways to mount more number of packages in a limited space.
Nevertheless, depending on the size of each individual package, only a certain number of packages can be mounted to a limited-size module substrate. This places limitations on the extent that the capacity of a memory module can be increased.
Further, in fabricating memory modules, solder balls in general are used to mount a number of packages on a module substrate. In such a case, the solder joint reliability is likely to be degraded due to certain undesirable solder ball characteristics, and this will lead to degradation of the reliability of the memory module as a whole.